High-resolution mass spectrometry (HRMS) and non-targeted analysis (NTA) provide an analytical platform for assessing occurrence of organic contaminants in aquatic environments across a broad swath of chemical space. Interest in using NTA in the context of large-scale monitoring efforts for evaluating chemical risk continues to grow. Here we present a case study on the use of NTA to evaluate the occurrence of per- and polyfluorinated substances (PFAS) in drinking water sources from more than 400 surface- and groundwater sites in North Carolina, USA. We developed and validated novel online-solid phase extraction (SPE) method that achieves low part-per-trillion detection limits for neutral, anionic and zwitterionic PFAS, using low-volume samples (10 mL). This method employs back-elution from a mixed-mode anion exchange column and peak focusing prior to ultra-performance liquid chromatography (UHPLC). We coupled online-SPE-UHPLC with electrospray ionization-ultra-high-resolution mass spectrometry (Orbitrap Fusion Lumos) with internally calibrated full-scan HRMS and data-dependent HRMS<sup>2</sup>. We have applied novel data treatment approaches to match analyses against databases of known PFAS chemicals as well as a custom PFAS MS/MS library. We have explored the utility of mass-defect filtering and defect-dependent analysis for elucidation of novel PFAS compounds. Furthermore, HRMS NTA results were integrated with sample-matched targeted quantitative analysis (UHPLC-QqQ) and compound-class specific endpoints (i.e., total organic fluorine) to evaluate co-occurrence trends and evaluate method coverage, respectively. Results indicate the widespread occurrence of emerging “ether-acid” PFAS compounds (e.g. GenX and related compounds) in the Cape Fear river basin of NC downstream of a major fluorochemical manufacturing facility as well as sporadic groundwater and surface water contamination from sources including firefighting foams and wastewater discharges. Our results represent the first state-wide map of holistic PFAS contamination in drinking water sources within the United States. Our discussion will focus on development and implementation of the NTA screening framework, with special consideration for chemical informatics tools used in developing and deploying the PFAS database and spectral library and establishing analytical figures of merit for identifications made in the absence of authentic standards, and report on the first completed round of sampling.

Applications of high-resolution mass spectrometry in large-scale emerging contaminant monitoring: Per- and polyfluorinated alkyl substance testing network in North Carolina

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.